A wireless mobile device with walkie-talkie functionality uses a half-duplex multicast system where one user may transmit an audio transmission across a certain channel to any plurality of recipients. This half-duplex transmission is transmitted over a Voice over Internet Protocol (VOIP) network, where voice conversations are routed to their destination over the internet via any series of routers and servers. In the half-duplex transmission, only one user may transmit an audio signal across a channel at any given time. Any plurality of recipients that are tuned into this channel may receive the audio transmission.
Typical walkie-talkie mobile devices require users to manually scroll through a list of channels to search for incoming transmissions. Once an audio signal is multicast over a channel, only those users that are already tuned into that channel may receive the audio transmission. Furthermore, if a user wishes to reply to a received audio transmission across a particular channel, the user must manually select the channel in question and then send the outgoing audio transmission.